Drifting Salinity measurement with GHL Profilux 4

[selcuksan]

Hi all,

I bought a GHL Profilux around July. After a tedious installation process, I start getting measurements for Salinity, Temperature, PH and ORP.

Salinity was spot on around 35ppt, also matching with my D&D refractometer. But then it started drifting to 34 ppt and stabilized around there. I didnt do any water changes, skimmer was skimming dry, and my Tunze Osmolator was working very well as ATO.

I am attaching a screenshot as well.

What do you think is causing this behavior?

 

[Lasse]

This probes should be in a very fast flowing environment. If you take up the probe and clean with a tooth brush - do the salinity measurements going back to 35 psu?

Sincerely Lasse